The objective of this study is to assess the blood pressure lowering effect of a single 300 mg oral dose of SR 49059 in African American and Caucasian hypertensive patients before, during, and after a hypertonic saline infusion. Based on pharmacology and both acute toxicology (LDO>2g/kg) and the 4-week repeated administration studies, and on preliminary safety data from the first single ascending oral dose tolerability trial, a minimal effective dose of 300 mg of SR 49059 is considered to be safe to be administered to humans. Twenty-four subjects completed the study and data is in analysis.